Back to EveryPatent.com
| United States Patent |
5,223,089
|
|
Kato
|
June 29, 1993
|
Method of deinking waste paper using a fatty acid polyoxyalkylene ester
Abstract
A method of deinking waste paper for reclamation thereof, which comprises
disintegrating waste paper with an alkali in water in the presence of a
fatty acid polyoxyalkylene ester having the formula
R--COO(PO)x(AO)y(PO)z--H
wherein R is an alkyl or alkenyl of 7-21 carbons, PO is an oxypropylene
group, AO is an oxyethylene group, or a mixed oxyalkylene group composed
of an oxyethylene group and at least one oxyalkylene group selected from
the group consisting of an oxypropylene group and an oxybutylene group,
and x is a numeral of 1-20, y is a numeral of 1-50, and z is a numeral of
1-50, as a deinking agent.
| Inventors:
|
Kato; Yasuo (Hyogo, JP)
|
| Assignee:
|
Nissin Kagaku Kenkyusho Co., Ltd. (Ehime, JP)
|
| Appl. No.:
|
847366 |
| Filed:
|
March 4, 1992 |
Foreign Application Priority Data
| Current U.S. Class: |
162/5 |
| Intern'l Class: |
D21C 005/02 |
| Field of Search: |
162/5
|
References Cited
| Foreign Patent Documents |
| 2243892 | Oct., 1987 | JP | 162/5.
|
| 2276093 | Nov., 1987 | JP | 162/5.
|
| 62-61711 | Dec., 1987 | JP.
| |
| 182489 | Jul., 1988 | JP.
| |
| 3165591 | Jul., 1988 | JP | 162/5.
|
| 64-11756 | Feb., 1989 | JP.
| |
Primary Examiner: Hastings; Karen M.
Attorney, Agent or Firm: Wenderoth, Lind & Ponack
Claims
What is claimed is:
1. A method of deinking waste paper for reclamation thereof, which
comprises disintegrating waste paper with an alkali in water in the
presence of a fatty acid polyoxyalkylene ester having the formula
R--COO(PO)x(AO)y(PO)z--H
wherein R is an alkyl or alkenyl of 7-21 carbons, PO is an oxypropylene
group, AO is an oxyethylene group, or a mixed oxyalkylene group composed
of an oxyethylene group and at least one oxyalkylene group selected from
the group consisting of an oxypropylene group and an oxybutylene group,
and x is a numeral of 1-20, y is a numeral of 1-50, and z is a numeral of
1-50, in an amount effective as a deinking agent.
2. The method as claimed in claim 1 wherein the fatty acid polyoxyalkylene
ester has the formula
R--COO(PO)x(AO)y(PO)z--H
wherein R is an alkyl or alkenyl of 7-21 carbons, PO is an oxypropylene
group, AO is an oxyethylene group, or a mixed oxyalkylene group composed
of an oxyethylene group and at least one oxyalkylene group selected from
the group consisting of an oxypropylene group and an oxybutylene group,
and x is a numeral of 3-15, y is a numeral of 20-40, and z is a numeral of
5-20.
3. The method as claimed in claim 1 wherein the fatty acid polyoxyalkylene
ester has a molecular weight of 300-8000.
4. The method as claimed in claim 1 wherein the fatty acid polyoxyalkylene
ester has a molecular weight of 1000-2000.
5. The method as claimed in claim 1 wherein the fatty acid polyoxyalkylene
ester has a molecular weight of 1700-2000.
6. The method as claimed in claim 1 wherein the fatty acid polyoxyalkylene
ester is used in an amount of 0.2-1.0% by weight based on the waste paper.
7. The method as claimed in claim 1 wherein the fatty acid residual in the
formula is the fatty acid residual of caprylic acid, capric acid, lauric
acid, oleic acid, myristic acid, palmitic acid, stearic acid, or a mixture
of these.
Description
FIELD OF THE INVENTION
This invention relates to a method of deinking waste paper for reclamation
thereof. More particularly, the invention relates to a method of deinking
waste paper such as newspapers or magazines using a specific fatty acid
polyoxyalkylene ester as a deinking agent in the known floatation method
to provide deinked pulp having a high degree of whiteness and low residual
ink droplet number.
DESCRIPTION OF THE PRIOR ART
Waste paper such as newspapers or magazines have been reclaimed by
disintegrating the waste paper to pulp fibers and then removing printing
ink components such as carbons or vehicles from the pulp fibers to recover
the pulp fibers for reuse as paper making material. The reclamation of
waste paper becomes more important on account of shortage of wood
resources and rise in their prices, and there is a strong demand for a
higher performance deinking agent since it becomes more difficult to deink
the recent waste paper on account of changes in the printing techniques,
printing systems and printing ink compositions.
The floation method has been known as a representative of the deinking
methods of waste paper for its reclamation. According to the floation
method, the waste paper is disintegrated with an alkali in water to
provide an aqueous slurry of pulp fibers, a deinking agent is added
thereto to remove the ink components from the waste paper and allow the
ink compositions to coagulate, blowing the air into the slurry so that it
foams and the ink compositions adhere to the foam, and then the foam is
removed from the slurry together with the ink compositions to leave
deinked pulp fibers. The resultant pulp fibers are bleached for reuse as
paper making material.
A variety of surfactants have been used as a deinking agent in the floation
method, and a higher fatty acid soap such as stearic acid soap is a
representative. The higher fatty acid soap has a high performance for
removing ink compositions from waste paper. However, the higher fatty acid
soap is not sufficiently foamable so that the coagulated and floated ink
compositions are incompletely removed, and thus the recovered pulp fibers
have still a many number of ink spots therein. There is also a tendency
that the released ink compositions deposit on the deinking device used.
Moreover, it is necessary to use the higher fatty acid soap in a large
amount to obtain intended deinking results, and accordingly the deinking
cost is high.
In order to solve these problems, there have been recently proposed a
number of deinking agents other than the higher fatty acid soap, among
which are anionic surfactants such as sodium alkylbenzenesulfonates,
higher alcohol sulfate salts, alpha-olefin sulfonates or dialkyl
sulfosuccinates; or nonionic surfactants such as higher alcohols,
alkylphenols, ethylene oxide and/or propylene adducts to higher alcohols
or alkylphenols. Very recently, there have been proposed a deinking agent
containing alkylene oxide adducts to higher fatty acids which is featured
by the presence of a carboxyl group residual bonded to a polyoxyalkylene
group, as disclosed in Japanese Patent Publication No. 61711/1987,
Japanese Patent Application Laid-open No. 182489/1988 and Japanese Patent
Publication No. 11756/1989 among others.
The above mentioned agents are improved in many respects compared with the
higher fatty acid soap, however, the ink removal performance when used in
the floation method is not satisfactory.
BRIEF SUMMARY OF THE INVENTION
It is, therefore, an object of the invention to provide a method of
deinking waste paper such as newspapers or magazines using a specific
deinking agent in the known floatation method to provide deinked pulp
having a high degree of whiteness and low residual ink droplet number.
The invention provides a method of deinking waste paper for reclamation
thereof, which comprises disintegrating waste paper with an alkali in
water in the presence of a fatty acid polyoxyalkylene ester having the
formula
R--COO(PO)x(AO)y(PO)z--H
wherein R is an alkyl or alkenyl of 7-21 carbons, PO is an oxypropylene
group, AO is an oxyethylene group, or a mixed oxyalkylene group composed
of an oxyethylene group and at least one oxyalkylene group selected from
the group consisting of an oxypropylene group and an oxybutylene group,
and x is a numeral of 1-20, y is a numeral of 1-50, and z is a numeral of
1-50, as a deinking agent.
DETAILED DESCRIPTION
The above fatty acid polyoxyalkylene ester used in the invention as a
deinking agent is structurally featured by that it has oxypropylene groups
bonded to the carboxyl group residual of the fatty acid and propylene
glycol residual at the end of the molecule.
Since the deinking agent used in the method of the invention contains the
above fatty acid polyoxyalkylene ester as a deinking agent which is
well-balanced in dispersibility and coagulating ability of ink
compositions, and thus the use of the deinking agent according to the
invention in the floatation method provides deinked pulp having a high
degree of whiteness and low residual ink droplet number.
The fatty acid polyoxyalkylene ester having an average molecular weight
preferably of 800-8000, more preferably 1000-2000, most preferably
1700-2000, is preferred since such an ester has especially eminent
deinking effects.
A further feature of the fatty acid polyoxyalkylene ester is that it is
liquid at normal temperatures, and can be added as it is to a
disintegrator when waste paper is disintegrated in water so that the
energy cost for deinking treatment is greatly reduced.
The fatty acid polyoxyalkylene ester may be produced by a known method in
which, as fatty acid components, there may be used, for example, caprylic
acid, capric acid, lauric acid, oleic acid, myristic acid, palmitic acid
or stearic acid. These fatty acids may be used singly or as a mixture. In
particular, stearic acid, palmitic acid or oleic acid is preferred on
account of high deinking performance.
In the above formula, AO is an oxyethylene group, or a mixed oxyalkylene
group composed of an oxyethylene group and at least one oxyalkylene group
selected from the group consisting of an oxypropylene group and an
oxybutylene group. Thus, the AO may be an oxyethylene group,
oxyethylene/oxypropylene group, oxyethylene/oxybutylene group,
oxyethylene/oxypropylene/oxybutylene group or an oxybutylene group. These
oxyalkylene groups may be in the form of random copolymers or block
copolymers.
According to the method of the invention, the fatty acid polyoxyalkylene
ester is used in the stage of disintegrating waste paper in water with an
alkali such as sodium hydroxide usually in an amount of 0.2-1.0% by weight
based on the waste paper, although not limited to the exemplified.
The method of the invention has an important feature in that the deinking
agent can be used as a one component agent. However, the agent may be used
in conjunction with any known deinking agent such as anionic surfactants
or nonionic surfactants, for example, a higher alcohol, a higher alcohol
sulfate salt, a sulfate salt of ethylene oxide adducts to higher alcohols
or alkylphenols.
As above set forth, the method of the invention uses such a specific fatty
acid polyoxyalkylene ester as a deinking agent in the floatation method
for waste paper reclamation, and thus the method provides deinked pulp
having a high degree of whiteness and low residual ink droplet number. In
addition, the deinking agent used is a one component liquid agent so that
it can be used easily and reduces the energy required in the floatation
method in the deinking process.
The invention will be described in more detail with reference to examples,
however, the invention is not limited to the examples.
EXAMPLES
Eighty percent by weight of waste newspapers (offset/relief ratio: 6/4) and
20% by weight of waste leaflets were cut into pieces and placed in a bench
disintegrator (JIS P-8209), to which were then added 1.5% by weight of
sodium hydroxide, 3.5% by weight of No. 3 sodium silicate, 1.0% by weight
of a 30% aqueous solution of hydrogen peroxide and 0.3% by weight of a
deinking agent indicated in Table 1, each based on the weight of the waste
paper, and then warm water so that the resultant aqueous slurry contained
the waste paper in an amount of 10% by weight. The waste paper was then
disintegrated at 55.degree. C. for 20 minutes. The resultant pulp slurry
was diluted to a pulp concentration of 1% by weight, and then the
floatation treatment was carried out at 30.degree. C. for 10 minutes with
the use of a testing floatator.
The resultant pulp slurry was formed into a sheet having a weight of 150
g/m.sup.2 using a standard type sheeting machine (JIS P-8209). The
whiteness of the sheet was measured with a Hunter whiteness meter
according to JIS P-8123. The residual ink droplet number was measured with
an image analyzer (.times.100). The results are summarized in Table 1.
TABLE 1
__________________________________________________________________________
Whiteness
Residual Ink
Average Molecular
Deinking Agent (%) Droplet Number
Weight
__________________________________________________________________________
Examples
1 C.sub.15 H.sub.31 COO(PO).sub.7 (EO).sub.15 (PO).sub.5 (EO).sub.15
(PO).sub.7 H 55.8 12 2678
2 C.sub.15 H.sub.31 COO(PO).sub.5 [(EO).sub.25 (EO).sub.5 ](PO).sub.5
55.2 11 2296
3 C.sub.17 H.sub.35 COO(PO).sub.10 (EO).sub.30 (PO).sub.10 H
56.6 14 2764
4 C.sub.17 H.sub.35 COO(PO).sub.10 [(EO).sub.30 (PO).sub.5 ](PO).sub.5
56.3 11 2764
5 C.sub.17 H.sub.33 COO(PO).sub.6 (EO).sub.40 (PO).sub.5 H
56.0 13 2506
6 C.sub.17 H.sub.33 COO(PO).sub.10 [(EO).sub.30 (PO).sub.5 ](PO).sub.20
55.8 15 3632
7 C.sub.17 H.sub.35 COO(PO).sub.7 (EO).sub.25 (PO).sub.6 H
57.3 8 1964
8 C.sub.17 H.sub.35 COO(PO).sub.5 (EO).sub.15 (PO).sub.12 H
57.6 7 1930
9 C.sub.15 H.sub.31 COO(PO).sub.10 (EO).sub.14 (PO).sub.10 H
57.4 7 1956
10
C.sub.15 H.sub.31 COO(PO).sub.3 (EO).sub.10 (PO).sub.15 H
57.1 6 1740
11
C.sub. 15 H.sub.31 COO(PO).sub.10 (EO).sub.5 (PO).sub.15 H
58.0 6 1926
Comparative Examples
1 C.sub.17 H.sub.35 COO(EO).sub.5 (PO).sub.10 (EO).sub.20 H
50.1 39 1964
2 C.sub.17 H.sub.33 COO(EO).sub.20 (PO).sub.10 H
51.7 37 1742
3 C.sub.15 H.sub.31 COO(EO).sub.15 H
50.3 33 916
4 C.sub.15 H.sub.31 COO(PO).sub.2 H
50.2 40 372
5 C.sub.17 H.sub.35 COO(PO).sub.20 (EO).sub.250 (PO).sub.20 H
50.3 42 13604
6 C.sub.15 H.sub.31 COO(PO).sub.20 (EO).sub.270 (PO).sub.20 H
50.0 38 14456
7 C.sub.17 H.sub.35 COO[(EO).sub.6 (PO).sub.15 ]H
51.1 35 1418
__________________________________________________________________________
NOTES: Oxyalkylenes in the brackets are in the form of random copolymers.
As seen in Table 1, the method of the invention provides deinked pulp
having a higher degree of whiteness and lower residual ink droplet number
than a method wherein a fatty acid polyoxyalylene ester which has
oxyethylene groups bonded to the carboxyl residual of fatty acid is used
as a deinking agent, and even than a method wherein a fatty acid
polyoxyalylene ester which has oxypropylene groups bonded to the carboxyl
residual of fatty acid, but has no such a structure as contains the AO
group between the oxypropylene groups bonded to the carboxyl residual of
fatty acid and the oxypropylene group at the end of the molecule.
It is also understood that the use of fatty acid polyoxyalylene ester which
has an average molecular weight of 1000-2000 provides the best results.
Top